The proliferation of data transport networks, most notably the Internet, has and continues to revolutionize telephony and other forms of real-time communication. Communication subscribers that have been accustomed to utilizing communication services carrying telephony traffic and data traffic over different systems are moving towards so-called “converged networks,” wherein telephone voice traffic and other forms of real-time media are converted into digital form and carried by a packet data network along with other forms of data. Various types of gateways allow for sessions to be established even among diverse systems such as Internet Protocol (IP) phones, conventional analog phones and Private Branch Exchanges (PBXs) as well as with networked desktop computers. Given the maturity of communication technologies, the transmission of voice over data transport offers many advantages in terms of reduced capital and operating costs, resource efficiency and flexibility. For example, at commercial installations, both initial investments and recurring costs for customer premise equipment are substantially reduced as most of the enhanced functions, such as Private Branch Exchange (PBX) and automatic call distribution functions, may reside in a service provider's network. However, the telephony services offered by the data network must be at least as feature rich and reliable as traditional telephony systems.
Undoubtedly, as business or residential communications subscribers begin using such voice-over-packet communications to replace conventional telephony, such subscribers will demand telephony services at least as good as conventional circuit-switched telephony systems. The engineering challenge has now focused on adapting Internet Protocol (IP) networks and other packet transport networks to provide reliable toll-quality connections. In addition, easy call set-up and enhanced features for supplying full-featured telephony as well as other forms of media transport are desirable. In terms of services, for example, subscribers, particularly business subscribers, are accustomed to certain call features, such as call forwarding and conditional call handling, which can be readily implemented via PBX features or network-resident “Centrex” services.
Therefore, there is a need for an approach for effectively supporting telephony features over a data network.